A fast screening procedure for water samples contaminated with chlorobenzene was developed. The volatile organic compounds were purged from water samples and their concentration was determined with ion mobility spectrometry (IMS) using corona discharge (CD) ionization. This analytical procedure permits the determination of chlorobenzene with a concentration range of 3–30 mg/l. The analytical results are available within 5 min. In order to test the general suitability of the method developed, the influence of sample matrix, especially of accompanying chlorinated aromatics, on ion mobility spectra of chlorobenzene was investigated.